1. Field of the Present Invention
This invention relates to a wax coating device, and specifically to a device for coating a corrosion protection wax on a vehicle body.
2. Description of the Prior Art
In recent years, it has been known to provide a corrosion protection wax coating on a lower surface of a floor panel of a finished vehicle. However, elements such as a fuel tank, exhaust pipe, parts for driving mechanism and the like or disposed at a lower portion of the vehicle tend to deteriorate workability of coating the floor panel. In view of the above, there has been installed a robot having multiple joints for controlling an application nozzle at a coating station to provide flexibility in executing the coating work to thereby get a homogenous and reliable coating.
The multiple joint robot is controlled based on teaching data stored in accordance with kind of the vehicle being transferred.
Japanese Patent Public Disclosure No. 62-114676, laid open to the public on May 26, 1987, discloses a triaxial type robot, the nozzle of which can move triaxially which is disposed by a transfer path for transferring the vehicle. The triaxial type robot is utilized for providing a coating a corrosion protection wax on a lower portion a of the vehicle.
Japanese Patent Public Disclosure No. 62-23796, laid open to the public on Oct. 17, 1987, discloses a corrosion protection wax coating device wherein a vehicle is supported and transferred by a truck having a transverse positioning device and a longitudinal positioning device so that the vehicle is accurately positioned for the coating work.
According to conventional corrosion protection wax coating work, a single coating robot is employed for the purpose of coating.
It should, however, be noted that the conventional manner for coating the corrosion protection wax on the floor panel is not efficient. This is because the workability in coating the corrosion wax on the floor panel depends on areas thereof. Generally, it is relatively easy to coat the wax on longitudinally opposite peripheral areas of the lower surface of the floor panel. On the other hand, it is relatively complicated to coat an intermediate area of the floor panel other than the peripheral areas because a lot of installations are disposed adjacent thereto so that a multiple joint type robot is needed for coating the intermediate area of the floor panel. It is not necessary to employ such a multiple joint type robot for coating the surface in order to obtain a desirable quality. Nevertheless, if a multiple joint type robot is applied for the coating work in coating the peripheral portions, time is consumed without utilizing the true merit of the multiple joint type robot, because control for the multiple joint type robot is complicated. In addition, the multiple joint type robot needs a broader space for moving a wax application nozzle thereof.
However, according to the conventional manner, there is no alternative but to utilize a multiple joint type robot because only one robot is allowed to be, installed at a given location. Therefore, a remarkable problem is produced in case where a thick coating is needed since a vehicle manufacturing line speed has been predetermined.
In this connection, the corrosion protection wax has normally, a thickness of 30 .mu.m for domestic use. However, a greater thickness of the corrosion protection wax coating, for example, 300 .mu.m, is required to provide a stronger corrosion protection effect in a foreign country, and specifically in a cold areas such as Northern Europe and North America where a salt is dispersed for preventing roads from freezing.